This invention relates to printed circuit boards (PCBs) especially to boards used to carry microprocessor-controlled circuits which are capable of being upgraded.
Conventionally, PCBs are used in complex equipment, such as the printer or dispenser in an automated teller machine; such items are designed to be capable of upgrades and improved functionalities. When a customer requests an upgrade, the whole PCB is replaced, although in many cases the upgraded functionality is provided simply by replacing a memory circuit, such as an EPROM, while the remainder of the circuit is unchanged. Naturally the manufacturer charges a substantial sum for the upgrade to each item of equipment in order to cover the original development costs.
Plug-in components such as EPROMS are however relatively easy to copy. There is a risk that, by dishonest copying of the EPROM or other memory device, PCBs can be upgraded without recourse to the manufacturer.